The present invention, in some embodiments thereof, relates to medical application and, more particularly, but not exclusively, to a method and system for assessing likelihood of sepsis.
Early detection of a disease condition typically allows for a more effective therapeutic treatment with a correspondingly more favorable clinical outcome. In many cases, however, early detection of disease symptoms is problematic due to the complexity of the disease; hence, a disease may become relatively advanced before diagnosis is possible. Sepsis represents one such class of diseases.
Sepsis is the name given to infection when symptoms of inflammatory response are present. Sepsis is defined as an infection-induced syndrome involving two or more of the following features of systemic inflammation: fever or hypothermia, leukocytosis or leukopenia, tachycardia, and tachypnea or a supranormal minute ventilation. Sepsis results either from community-acquired infections or hospital-acquired infections.
The cause of a sepsis can be infection of any origin, including bacterial, viral and parasitic origin, or it can be caused by fungi. This infection can occur anywhere in the body. The most common sites of infection in patients with sepsis are lung, gut, urinary tract, and primary blood stream site of infection. Since sepsis can be caused by many types of infection with microorganisms at many different sites, sepsis is a very heterogeneous disease.
Sepsis can affect anybody at any age, although young or very old hospital patients and persons with existing disease conditions have a higher risk. Risk factors include a too little active immune system (as can arise, for example, during a chemotherapy or is caused by medicine intended to permit an organ transplantation; by surgical procedures; artificial respiration; genetic predisposition or in invasive procedures, such as the supply of liquids).
Severe sepsis is defined as sepsis associated with acute organ dysfunction, wherein the risk of death from sepsis increases with increasing severity. Sepsis is the leading cause of death in critically ill patients, particularly among patients in non-coronary intensive care units.
The course of the sepsis can be described as a sequence of various processes. When the sepsis begins, the body reacts with expanded inflammations, blood clotting and impaired decomposition of blood clots.
Under normal circumstances, substances, also referred to as immunomodulators, are released in order to support the body in combating the infection during the healing process itself. With a person suffering from sepsis, this mechanism breaks down and the immunoregulators lead to an overshooting reaction. The infection enhances the release of too many of these regulators which inflame the lining of the blood vessels and the processes for blood coagulation are activated, this process triggering another wave releasing regulators.
The inflammation leads to the release of a substance stimulating the formation of blood clots. In the sepsis cascade, the body's ability to decompose the blood clots is suppressed. A substance involved in the formation of the blood clot, the control of the inflammation and the decomposition of clots, referred to as activated protein C, is reduced in a sepsis. As a result of the formation of blood clots and the inability to decompose these clots, microscopic blood clots start to deposit in vital organs, arms and legs and restrict the blood flow leading to tissue damages which can lead to organ failure.
Sepsis is typically diagnosed either by clinical criteria or by culture of microorganisms from the blood of patients suspected of having sepsis plus the presence of features of systemic inflammation. Bloodstream infection is diagnosed by identification of microorganisms in blood specimens from a patient suspected of having sepsis after 24 to 72 hours of laboratory culture. For each class of infection, there are several different types of microorganisms that can cause sepsis.
Techniques for early detection of sepsis are found in, e.g., U.S. Pat. Nos. 8,029,982 and 7,941,199, and in U.S. Published Application Nos. 20110118569, 20030194752 and 20060246495.